Over deze norm
||Programming languages , their environments and system software interfaces
Since the extensions described in this technical specification are experimental and not part of the C++ standard library, they should not be declared directly within namespace std. Unless otherwise specified, all components described in this technical specification either: - modify an existing interface in the C++ Standard Library in-place, - are declared in a namespace whose name appends ::experimental::concurrency_v1 to a namespace defined in the C++ Standard Library, such as std, or - are declared in a subnamespace of a namespace described in the previous bullet, whose name is not the same as 2 an existing subnamespace of namespace.
||Programming Languages - Technical specification for C++ extensions for concurrency